IRRADIANCE RESPONSIVITY AND UNEQUIVOCAL TYPE-1 PHASE RESPONSIVITY OF RAT CIRCADIAN ACTIVITY RHYTHMS
IRRADIANCE RESPONSIVITY AND UNEQUIVOCAL TYPE-1 PHASE RESPONSIVITY OF RAT CIRCADIAN ACTIVITY RHYTHMS
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DOI：
10.1152/ajpregu.1992.263.5.r1110
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发表时间：
1992-11-01
影响因子：
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通讯作者：
BAUER, MS
中科院分区：
文献类型：
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作者：
BAUER, MS
光诱导啮齿动物昼夜节律相移的行为学、神经药理学和分子研究仔细评估了光响应性的相依性。然而，关于这种效应对所使用的光刺激的持续时间和辐照度的依赖性的信息要少得多。在这项研究中，非常短(5分钟)的50MUW/cm2(175lux)的白光脉冲给蒙面大鼠产生了明确的1型相位响应性，周期没有显著变化，相移可变性与使用更长、更高强度脉冲的研究相当。在相位响应曲线的相位延迟、相位超前和交叉部分显示出与辐照度的相关性，即使在非常高的辐照度下，在死区也可以看到最小的相移。这些结果表明，与通常用于研究大鼠昼夜节律对光反应的神经机制相比，较短、强度较小的光刺激可以获得最大相移幅度。
Behavioral, neuropharmacological, and molecular studies of light-induced phase shifting of rodent circadian rhythms evaluate carefully the phase dependence of light responsivity. However, much less information is available regarding the dependence of such effects on the duration and irradiance of the photic stimulus used. In this study, very brief (5-min) white light pulses of 50 muW/cm2 (175 lux) administered to hooded rats elicited unequivocal type-1 phase responsivity, without significant changes in period, and with phase shift variability comparable to that in studies using longer, higher intensity pulses. Irradiance dependence was demonstrated in the phase-delay, phase-advance, and crossover portions of the phase-response curve, with minimal phase shifting seen during the dead zone even at very high irradiance. These results indicate that maximal phase-shifting magnitude may be achieved with shorter, less intense photic stimuli than are often used in studies of the neural mechanisms involved in light responsivity of rat circadian rhythms.